musser



Nov. 29, 1960 c w. MUSSER 2,961,897

VARIABLE GEAR RATIO HANDWHEEL Filed April 9, 1958 2 Sheets-Sheet 1 a INVENTOR x i o WALTON MUSSER Nov. 29, 1960 c w. MussER 2,951,397

VARIABLE GEAR RATIO HANDWHEEL Filed April 9, 1958 2 Sheets-Sheet 2 INVENTOR G WALTON MUSSER VARIABLE GEAR RATIO HANDWI-IEEL C Walton Mnsser, Beverly, Mass, assignor to the United States of America as represented by the Secretary of the Army Filed Apr. 9, 1958, Ser. No. 727,505

1 Claim. (Cl. 74-798) (Granted under Title 35, US. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government for governmental purthe object to its final position. An important object is to provide an improved control assemblage wherein a single member is utilized (1) to select between the different speeds of such a mechanism and (2) to drive the mechanism at the selected speed. A further object is the provision of an improved gun aiming mechanism adapted to be driven by such a control assemblage.

In the operation of gun aiming mechanisms, it has been customary to position the gun approximately by rotation of a handwheel and to adjust the gun to its final position by means of a vernier knob located at the center of the handwheel. This type of control is satisfactory in the case of a stationary target. Where the target is moving, however, the time taken to move the hand of the operator from the handwheel to the vernier knob renders it unsatisfactory. The present invention avoids this difficulty by mounting on the rim of the handwheel a knob which is utilized to drive the handwheel and is associated with means which are operable to select either speed without interrupting movement of the gun.

The invention will be better understood from the following description when considered in connection with the accompanying drawings and its scope is indicated by the appended claim.

Referring to the drawings:

Fig. 1 illustrates a type of gun to which the invention is applied,

Fig. 2 is a view, mostly in section, illustrating the control assemblage as applied to a preferred form of traversing mechanism, and

Figs. 3, 4 and 5 are explanatory diagrams relating to the operation of the mechanism of Fig. 2.

Fig. 1 illustrates a gun 10 which is mounted on a support 11 and is associated with a spotting rifle 12. Elevation of the gun 10 is controlled by a handwheel 13 and traversing of the gun is effected by a handwheel 14. The handwheel 14 operates a traversing mechanism 15 and the handwheel 13 operates an elevation mechanism 16. An arm 18 is interposed between these two mechanisms. As will appear a control assemblage, hereinafter described, is applicable to either of these mechanisms.

Fig. 2 illustrates a gun traversing mechanism wherein a cylindrical member 17, fixed to an arm 18, is rotated for aiming the gun 10 of Fig. 1. Rotation of the member 17 is efliected by rotation of the handwheel 14, the relation between the rotational speeds of the handwheel 14 and the member 17 being determined by the position of a vertically adjustable control knob 19.

Interposed between the control knob 19 and the gun aiming mechanism is a speed selector lever 20 which is pivoted at 21 and is biased to either of two positions by a spring 22.

In the illustrated position of the selector 20, the handwheel 14 is coupled to the cylindrical member 17 through the knob 19, the selector 20, a vernier knob 23, a shaft 24, friction type sun rollers or gears 25, friction type planet rollers or gears 26 and 27, friction type ring gears 28 and 29, and a cap 30. With this position of the selector 20, the member 17 and arm 18 are rotated at a relatively low speed.

With the selector 20 in its lower operating position opposite that shown in Fig. 2, the handwheel 14 is coupled to the member 17 through the knob 19, the selector 20, a member 31 which is keyed to a planet carrier 32, planet rollers 26 and 27, rings 28 and 29 and the cap 39. With the selector 20 in this position the arm 13 is moved at a relatively high speed. h

In this connection, it should be noted that the handwheel is supported by a closed roller bearing 33 which is supported from the member 31 and that the change from one speed to another is readily effected without interrupting rotation of the'handwheel.

The traversing mechanism of Fig. 2 also includes a free traverse adjustment including a locking plate 34 and locks 35 shown as positioned in slots 36 at the bottom of the ring 29. In this position, the ring 29 is fixed in position and the arm 18 is driven as described above.

The locks 35 are eight in number and are spring loaded I toward the center of the lock plate 34 by springs 37. The

shaft 24 is splined to sun rollers 25 and has near its lower end a conical cam-shaped surface adapted to engage the inner ends of the locks 35 for disengaging the locks from the slots 36. When the conical cam is lifted by the button 23, the locks 35 are forced outwardly. This permits the arm 18 to swing freely until the knob 23 is depressed to its illustrated position and the locks 35 engage the slots 36.

The gun aiming mechanism of Fig. 2 may be utilized for either elevation or transverse adjustment. In it the usual gears have been replaced with prestressed rollers to eliminate the backlash that is normal for gear trains. Due to the pre-loading these rollers are given during their original assembly, they are forced into such intimate contact that their surfaces can be visualized as interlocked with microscopically small teeth. The operation of the mechanism is now to be explained with reference to Fig. 3 wherein the various parts have the same reference numerals as in Fig. 2 and are given specific dimensions.

The operational principle can be likened to a lever. As shown in Figs. 4 and 5, the end of the lever moves 2 inches while the central point only moves 1 inch. If this central point were the length of the lever from the fixed end, it would move V of 2 inches or only 0.02 inch.

If the lever is replaced by a step roller having a 2 inch and a 1 inch diameter, rolling the 2 inch roller a distance of 2 inches will produce a movement of 1 inch to an object rolling on the circumference of the 1 inch diameter roller. For rollers of any diameter when rolling on flat surfaces, the ratio is:

Distance traveled by center of rollers Distance traveled by surface rolling on small roller Diameter of large roller Dia. of large roller minus the din. of small roller Dia. of ring 29 Dia. of sun Patented Nov. 29, 1960- and the factor which corrects for the curved path of the v planet rollers:

Dia. of ring 28 Dia. of planet carrier For the dimensions shown on Figure 3, the ratio between the sun and ring 28 would be:

Dia. planet 27 Dia. planet 2? Dia. Planet 26 X (Dia. of ring 29 Die. Sun

Ratio Dia. ring 28 Dia. planet carrier For the elevating mechanism used in the T149E3/M79 mount, these calculations are:

Ratio 2 5 1 I claim:

The combination with a support, of a rotatable member carried by said support, and mechanism for driving said member at different speeds, said mechanism including friction type ring gears one of which is fixed to said support and the other of which is fixed to said member, a carrier, unitary friction type planetary gears supported by said carrier, and each of said planetary gears being prestressed against the interior of both of said friction type ring gears, friction type sun gears prestressed against said friction type planetary gears, a shaft extending through and rotatable with respect to said carrier, said shaft being fixed to said sun gears, a handwheel, and a selector for coupling said handwheel to one of said shaft and carrier whereby said rotatable member may be driven from said handwheel through either said carrier, friction type planetary gears and friction type ring gears at one speed or through said shaft, friction type sun gears, friction type planetary gears and friction type ring gears at another and slower speed than that through said carrier.

References Cited in the file of this patent UNITED STATES PATENTS 1,122,500 Henry Dec. 29, 1914 1,299,765 Norton et al Apr. 8, 1919 2,382,110 Sheldrick et a1 Aug. 14, 1945 2,484,273 Desmoulins Oct. 11, 1949 2,555,671 Baia June 5, 1951 2,713,274 Lockwood July 19, 1955 

